Position a rack in the middle of the oven and preheat to 350 degrees F. Grease a 9-inch spring-form pan with nonstick spray, line with parchment paper, and gluten free flour or almond meal.
In a large bowl, whisk together the egg yolks and all but 2 tbsp of the sugar. Whisk vigorously until the yolks become thick and pale yellow in colour, about 2 minutes. Whisk in the vanilla extract and the salt and set aside.
In the bowl of a standard electric mixer fitted with the whisk attachment (or a bowl with a hand mixer), beat the egg whites on medium speed until they become opaque, about 1 minute. Sprinkle in the remaining 2 tablespoons of sugar, and continue to beat the egg whites until they hold medium peaks.
With a flexible rubber spatula, stir in about 1/4 of the egg whites to the egg yolk mixture (no need to be gentle here). Scrape the remaining egg whites over the yolks, and add about half of the almond flour. Gently begin to fold the egg whites and almond flour into the yolks. While the mixture still has a few streaks of white left, add the remaining almond flour and fold in. Continue gently folding until you have a homogeneous batter. Pour the batter into the prepared pan and lightly shake the pan until the batter is level.
Bake the cake for about 35 minutes, until the top is golden brown and springy to the touch. Let the hot cake cool on a wire rack for 5 minutes, then run a butter knife along the edges of the cake pan.
Invert the cake pan onto the rack, remove the sides and bottom, and peel away the parchment paper. Turn the cake right side up and allow to cool completely.
Dust with powdered sugar, cut into 12 slices and serve with fresh berries.